Bottom pain & prep work?

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TomR's picture
TomR
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Joined: 12/4/17
Posts: 38
Bottom pain & prep work?

I bought my 2000 C36MkII (Hull 1998) in March 2018. Bottom paint was only 1 year old and in good shape so I didn't do an any work on the bottom except some touch up areas. This fall when she was hauled I was suprised how clean the hull was. I sail in the North East River of the Chesapeake and there is quite a bit of freshwater. I was told by other sailors this is quite normal. So I plan to get at least one more year out of my bottom paint.
   
However, it looks like there will be more work than a year ago. The previous owner gave me 1&1/2 gals of left over Pettit Ultima SR40 (Ablative). Figure I'll paint 1 foot below the waterline and various spots which need some work. My question is what number sand paper do people use. Also do people usually wear coveralls and put on a face mask? Figure the dust is not good to breath and be around. I'll probably hand sand if I can.
  
I also wire brushed my prop and shaft last spring and sprayed on Pettit prop coat. Will do the same again. Zinc's look good. Almost the same as when I put them on. Do sailors replace those every year no matter what? 
 
Just trying my first real spring prep bottom job. Any suggestions?

Thanks much,
Tom R, ObLaDi ObLaDa, C36MkII, 1998

Tom Runiewicz
ObLaDi ObLaDa
Catalina 36 MkII, Wing Keel, Tall Rig
Hull #1998
North East, MD
 

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Siler Starum
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Joined: 4/20/18
Posts: 113

In the attached product sheet you can find all important information.
How we approach our bottom job: I try to let the high pressure wash to do most the job and when sanding on spots is needed I do this by means of wet-sanding, never dry. The dust is from the old antifouling is not the most healthy stuff and good personal protection is absolutely a must.
We use the system International Micron LZ and our sailing-area is also mostly in fresh-water area's. As it is self-polishing during the time the product disappears.
Therefore we have the habit not to do touch-ups but just repaint the whole underwater-hull when we have our lady out of the water. It takes only around 2.5-liter of product to cover the complete underwater area including an extra layer on the waterline.
We have not zinc but aluminium anodes on the hull and prop-shaft as we are most the time in fresh-water and the hull anode is more effected by the fact that it is used as ground for the 12VDC-system then for compenstation of corrosion, but not needed to be renewed that oft. 
Prop-coat we don't use. I think it is a waste of money as if you don't have a proper surface preparation it will be off after before you left your mooring spot.

Durk Nijdam
S/V "SILER"
Catalina 36MKII - 2001 / hullnr. 2013
Stavoren - Holland

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Chachere's picture
Chachere
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Tom -
First, plan for decent personal protection.  This stuff is toxic -- that's why it works! -- and my belief is that no boat is worth ingesting a product that the federal EPA lists as a possible carcinogen, endocrine disrupter, and developmental or reproductive toxin.  You need more than a paper facemask (as Don Casy puts it in his seminal "This Old Boat", paper face masks are as useful as paper condoms, unless you intend to barnacle proof your nostrils and lungs); get yourself a decent respirator that covers mouth and nose and fits properly.  Also well fitting goggles.  Also a couple of disposable tyvek full body coveralls, including hood and booties (they are inexpensive protection at maybe $5 each).

Second, if you are fortunate enough to have lucked into one of the increasingly rare finds -- a boatyard that allows you to do your own bottom prep -- they generally are going to require the use of equipment to control dust.  This is in part because of environmental regulations, and as well because the owners of your neighboring boats generally won't appreciate your covering their boats with airborne toxic paint dust.  I use an orbital sander (with various hook-and-loop grades of paper, usually from 80 to 120 grit)  which has a dust exhaust port sized to be attached to a hose for a shop vac (with a good filter and bag to prevent it just being blown out the vacuum exhaust).   There are some low-cost designs out there for DYI dust collection systems that use a 5 gallon pail, such as here:  www.instructables.com/id/Cheap-Easy-DIY-Dust-Collector/

Lastly, I'm not surprised by the longevity you're finding with the paint.  We sail exclusively in salt water in the US northeast, and have been using the same paint as you -- actually, West Marine's PCA Gold, which is just rebranded Petit Utima SR 40 -- for most of this decade.  We found we can get by with 3 seasons with one coat on most of the hull plus a second coat around the waterline, the rudder, and the leading edges of the keel.  So we tend to haul out only every third year, and leave the boat in the water during the other 2 winters. 

Oh, and as for the prop, there does not appear to be a magic cure.  We coat it with some sort of grease (such as Lanocoat) to hopefully make it harder for the critters to stick on...

 

Matthew Chachère
s/v ¡Que Chévere!
(Formerly 1985 C36 MKI #466 tall rig fin keel M25)
2006 Catalina Morgan 440 #30.
Homeported in eastern Long Island, NY

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